On 15/03/13 13:11 -0700, [email protected] wrote:
> The feature of "composite  primary keys" is very handy, but let me address 
> it from a different point of view. 
> When importing data into any "relational Software" like Tryton, you might 
> want to update existing records or add new records if none is existing | 
> where record is an instance of an real life object. With just a primary key 
> it is basically never possible to do that without intensive scripting and 
> still that's not save, more than one record might apply for a rule. A 
> record never can be identified by an integer "primary key" from the outside 
> world. 
> Using composite keys, I call them "Identifying fields", implemented on 
> class level, where never an object can be added violating the unique key 
> "field a and field b ...field c ...  and field n" makes sure, that when 
> importing data the decision of "update an existing record" or "add a new 
> one" is distinct (deleting is not covered here). 

I don't see why you need primary composite key just use a unique index
which is supported by Tryton.

-- 
Cédric Krier

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